In the context of suction in a vacuum system, two common units of measurement are:
Pascal (Pa): The Pascal is the SI unit of pressure and is used to measure the suction or vacuum pressure. One Pascal is defined as one Newton per square meter. It is a small unit, and vacuum pressures are often expressed in kilopascals (kPa) or millipascals (mPa) for practical purposes.
Torr: The Torr is a non-SI unit of pressure, but it is commonly used in vacuum technology. It is named after Evangelista Torricelli, the Italian physicist who invented the mercury barometer. One Torr is equivalent to 1/760th of standard atmospheric pressure at sea level, which is approximately 133.322 Pa.
In various applications, other units like inches of mercury (inHg) or millimeters of mercury (mmHg) might also be used to measure vacuum or suction, particularly in industries or countries that have not fully adopted the SI system. However, it's worth noting that the SI unit of pressure, the Pascal, is becoming increasingly prevalent and is the standard in scientific and industrial contexts.